Hi, does your car seat have a detachable cushioning? If yes then pull those sections off and wash on gentle cycle in washer with vinegar or baking soda thrown in.

If no, then hand wash with a good Lysol or bleach water. Allow to dry good and if the smell is still there then grab a garbage bag and toss in baking soda or clean cat litter and tie the car seat up in the garbage bag. It will work. Good luck, Maryjo

Try spraying lightly (do not saturate) with white vinegar. It may take a few applications but that should get rid of the moldy smell and the vinegar smell will fade after a day or so. If all else fails, try febreeze or a similar store brand. While I hate to advocate chemical solutions, this has been the only solution to some nasty odors in our car. Our son suffers from car sickness frequently and we have learned to keep a bottle in the trunk for emergencies.

Spray Bottle, 70% rubbing alcohol and water. Mix all them together and spray the seats. The rubbing alcohol kills the bacteria that are causing the molds and the odor. Park your car in a sunny spot, spray the seats, rolled down the windows just a little bit. Its works every time.